An effective training method to use is the addition of chain links to a bar. The chains hang from the bar, and as the bar is lowered, the chains gradually pile up on the ground effectively unloading the bar of the additional weight. For example, if you use 50lbs of chains per side on the bench press and that half the chains are on the floor in the bottom position and none of it are on the floor at the top you have an overload of 50lbs at the top of the range of motion. This allows you to increase resistance at the strongest portion of a lift, making you work hard through all the range of motion to complete the lift.

Chains are often associated with jumpstretch bands because they are used to increase the load during the concentric portion of the movement, as you reach stronger joint angles.

However the chains and bands differ in one very important way: the bands are actually trying to throw down the bar toward you (bench press) or throw you down (squat). So basically the bands provide an eccentric acceleration component that must be countered via muscle action.

The bands on the other hand are only added weight. The more chains are resting on the floor, the less weight is added to the bar and vice versa. However, contrary to the bands, chains don’t have that eccentric acceleration component. They simply allow you to increase the resistance during the movement.